Fabrics used in children's apparel should have characteristics such as softness, excellent colorability, color fastness, and acceptable crocking. Furthermore, it is advantageous that the apparel be somewhat stain-resistant. Many consumers prefer cotton, both because it is a natural fiber and because it is typically soft. Fabrics used in children's apparel and in similar applications, however, typically exhibit inferior performance in terms of crocking, abrasion resistance, color fastness, stain resistance, and shrinkage.
Cost is an important factor in children's clothes. The material processing and dying processes used in the manufacture of children's apparel is different than those used for applications such as adult apparel. For example, children's apparel may be printed with a combination of pigments and an adhesive gum, in contrast to the more expensive reactive dyes used in adult clothing. A fixing agent is typically used to improve fastness because the colorant pigments do not readily migrate into cellulose fibers or fix onto them. Soft polymeric adhesive binders or resins are used as fixing agents. Other useful fixing agents include alum, caseins, starches, acrylics, rosin sizes, polyvinyl alcohols, and cationic colorant fixatives. They improve durability by encapsulating and binding pigment to fiber surfaces. Binders and resins only modestly improve durability because they are a surface treatment and generally have only moderate fastness. Binders or resins also stiffen textile-like aesthetics while often having a negative impact on liquid distribution and absorbency properties.
Crocking is a transfer of color from the surface of a colored fabric to an adjacent area of the same fabric or to another surface principally by rubbing action. Crockfastness is color fastness to rubbing. Deeper shades of color require excess pigment and binder or resin that tend to rub off or crock. To obtain a navy blue color with acceptable crocking using this dying process results in an unacceptably stiff garment. Improving crockfastness/colorfastness of dyed textile fabrics has been an ongoing problem in the textile industry.
Current techniques to improve one or more characteristics, for example crocking, results in diminished performance at least in terms of hand and also usually in terms of shrinkage. Furthermore, the treatments exhibit poor fastness to the fabric during washings.
It is known to graft certain chemicals on to cotton fiber. U.S. Pat. No. 2,789,030 discusses a method of modifying a cellulose fabrics with acrylate monomers, modified by glyoxals. U.S. Pat. No. 3,989,454 teaches grafting acrylate, especially ethyl acrylate monomers, onto cotton and mercerized cotton using high energy gamma radiation as an initiator and a water/methanol as the solvent. U.S. Pat. No. 4,901,389 teaches a grafting reaction for a fiber material where free radicals are formed, and then adding fluorinated monomers, particularly fluorinated acrylates, which are grafted. The graft is beneficially aided by adding a graftable derivative of morpholine, i.e., the morpholinoethyl acrylate. U.S. Pat. No. 4,737,156 discloses use of cationic cellulose graft copolymers for improving dye fastness to a dyed textile substrate by post dye application (top up). U.S. Pat. No. 4,524,093 discloses a latex coating composition of an emulsion of acrylate monomers and a glyoxal curing resin.
One method to improve the hand is to treat the fabric with a softener. The use of silicones for softening fabrics, i.e., providing lubrication between fibers and yarns so they move over one another more easily, has been well known for quite some time. In addition, the use of organomodified silicones for textile treatments has also been well documented over the years (See U.S. Pat. Nos. 4,620,878; 4,705,704; 4,800,026; 4,824,877; 4,824,890; and 5,173,201, each of said patents being incorporated herein by reference. Silicones of this type are typically delivered to textiles in the form of an aqueous emulsion.
Other silicone fluids, for example polydimethylsiloxanes, provide additional benefits such as improved fabric feel. Examples of these preemulsified silicones are 60% emulsion of polydimethylsiloxane (350 cs) sold by Dow Corning Corporation under the trade name DOW CORNING 1157™ Fluid and 50% emulsion of polydimethylsiloxane (10,000 cs) sold by General Electric Company under the trade name General ElectricSM 2140™ Silicones. Such compositions are usually added to either the wash or rinse water of a laundering operation. They are typically aqueous based, water dispersible microemulsions which contain from about 0.1% to about 15% of the microemulsified functional silicones. The compositions are diluted in the wash or rinse.
U.S. Pat. No. 5,616,758 describes cationic silicone compositions that can be employed as a lubricant for fibers such as polyester, nylon, acrylic, aramides, cotton, wool, and blends thereof. The use of silicone compounds in the treatment of synthetic fibers is known in the art. See, for example, the discussion of epoxy silicones in U.S. Pat. No. 2,947,771. Such silicone compounds are effective in both providing increased lubricity of the fiber and improved softness for fabrics made from these fibers. However, epoxy silicones suffer from the disadvantage that they only possess a limited durability when employed with synthetic fibers.
The art has also looked to certain aminosilicones in the treatment of fibers. Because these silicones possess no net charge, they cannot effectively cling, generally by electrical attraction to cellulosic or proteinaceous materials. In fact, when used in connection with conventional polyester fiber/cotton blends, the aminosilicones will cling only to the polyesters within the blends. In an attempt to overcome these problems, it is known to use cationic compounds which are adhere to the cellulosic materials. Certain cationic compounds such as certain specific cationic polyorganodisiloxanes (see, for example, U.S. Pat. No. 4,472,566) and quaternary nitrogen derivatives of organosiloxanes (such as those discussed within U.S. Pat. No. 4,185,087) are known in the art. Other suitable fabric softening compounds are the nonquaternary amides and the nonquaternary amines. A commonly cited material is the reaction product of higher fatty acids with hydroxy alkyl alkylene diamines. See U.S. Pat. Nos. 4,460,485; 4,421,792; and 4,327,133.
U.S. Pat. No. 2,952,892 describes a method of modifying cellulosic fibers with a composition including acrylic prepolymers and silicone resins such as alkyl polysiloxanes. U.S. Pat. No. 5,951,719, the disclosure of which is incorporated by reference, discloses a method of treating a cellulose fabric with a composition containing acrylates, glyoxals, and silicone textile softeners to improve color-fastness on dyed cotton
U.S. Pat. No. 5,741,548, the disclosure of which is incorporated by reference, teaches a process of chemically bonding a polymeric coating, that is, acrylic prepolymers, urethane prepolymers, and acrylic urethanes, to many fibers, including cellulosic cotton. This patent describes the use of graft initiators such as iron salts and peroxides such as urea peroxide. The purpose of the graft is to provide a surface capable of binding ink-jet printing for high resolution imaging.
U.S. Pat. No. 5,552,472, the disclosure of which is incorporated by reference, teaches a solution for forming a grafted substance containing an initiator, a catalyst, a water-dispersible prepolymer, and a monomer. The graft controls fabric porosity, and is useful for controlling the permeability of air bags. One composition contains a graft initiator, for example a metal ion; a catalyst, for example peroxide, peracid, or perbenzoate; a grafting prepolymer, for example water-dispersible urethanes; and a monomer, for example acrylic.
U.S. Pat. No. 5,763,557, the disclosure of which is incorporated by reference, teaches a polymeric composition which is applied by chemical grafting that involves the use of monomers/prepolymers, catalyst, graft initiator and other ingredients of the composition. The coating is beneficially applied to reemay and satin acetate fabric allows to undergo graft polymerization thereby forming a polymeric film which is chemically bonded to the fabric substrate with strong adhesion. The preferred composition contains a graft initiator, for example a metal ion; a catalyst, for example a peroxide; a grafting prepolymer, for example urethane and/or acrylic; a monomer, for example acrylic; and a sodium salt of AMPS monomer.
U.S. Pat. No. 6,165,919 teaches a process whereby cellulosic materials such as cotton fabrics and paper are crosslinked with a composition comprising (A) polymers of ethylenically unsaturated polycarboxylic acid monomers or salts thereof, the monomers having one or more dicarboxylic groups wherein the carboxyl groups are on adjacent carbon atoms; (B) saturated alpha-hydroxypolycarboxylic acids or salts thereof; and (C) one or more curing catalysts, and heated to produce esterification and crosslinking of the celluose by reaction of the cellulosic hydroxyl groups with carboxyl groups in the reaction product of (A) and (B).
Treatments of paper with formaldehyde-based reagents, such as dimethyloldihydroxylethyleneurea, urea-formaldehyde, and melamine-formaldehyde, have been used as wet strength agents to impart these valuable characteristics on cellulosic fiber. However, formaldehyde is an irritant and a known carcinogen. In addition, cellulosic fabrics treated with formaldehyde-based reagents suffer severe strength loss. As a result there are stringent limits on the formaldehyde-production from textile garments. Glyoxylated polyacrylamide-diallyldimethyl ammonium chloride copolymer resins are also known for use as dry strength and temporary wet strength resins for paper.
The art teaches many formulations for increasing color-fastness, improving hand, and reducing shrinkage. What is needed is an inexpensive composition and process whereby fabric, especially for cotton and cotton-poly blends, can be readily treated to reduce crocking, increase color fastness, reduce shrinkage, wherein such treatment does not adversely affect the hand. Preferably, the treatment can endure at least 20 washing cycles with little degradation in performance. Preferably, the treatment that can be applied without adding special processing steps to the fabric. The treatment beneficially is in a single stable composition with a shelf life of at least two months. The compositions of the present invention solve these needs.